Jack Element with a Stop-off

ABSTRACT

In one aspect of the present invention, a drill bit has a body intermediate a shank and a working face, the working face comprising a plurality of blades formed on the working face and extending outwardly from the bit body. Each blade comprises at least one cutting element. The drill bit also has a jack element coaxial with an axis of rotation and extending out of an opening formed in the working face. A portion of the jack element is coated with a stop-off.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional of U.S. patent application Ser.No. 11/750,700, which is a continuation-in-part of U.S. patentapplication Ser. No. 11/737,034 which is a continuation-in-part of U.S.patent application Ser. No. 11/686,638, now U.S. Pat. No. 7,424,922,which is a continuation-in-part of U.S. patent application Ser. No.11/680,997, now U.S. Pat. No. 7,419,016, which is a continuation-in-partof U.S. patent application Ser. No. 11/673,872, now U.S. Pat. No.7,484,576, which is a continuation-in-part of U.S. patent applicationSer. No. 11/611,310, now U.S. Patent Publication No. 2008/0142264, whichis a continuation-in-part of U.S. patent application Ser. No.11/278,935, now U.S. Pat. No. 7,426,968, which is a continuation-in-partof U.S. patent application Ser. No. 11/277,3294, now U.S. Pat. No.7,398,837, which is a continuation-in-part of U.S. patent applicationSer. No. 11/277,380, now U.S. Pat. No. 7,337,858, which is acontinuation-in-part of U.S. patent application Ser. No. 11/306,976, nowU.S. Pat. No. 7,360,610, which is a continuation-in-part of Ser. No.11/306,307, now U.S. Pat. No. 7,225,886, which is a continuation-in-partof U.S. patent application Ser. No. 11/306,022, now U.S. Pat. No.7,198,119, which is a continuation-in-part of U.S. patent applicationSer. No. 11/164,391, now U.S. Pat. No. 7,270,196. All of theseapplications are herein incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to the manufacturing of drill bitassemblies for use in oil, gas and geothermal drilling. Drill bitstypically have a number of cutting elements brazed onto a drill bitbody. Such cutting elements generally comprise a diamond surface bondedto a carbide substrate, which substrate is generally brazed into pocketformed in the body of the drill bit.

U.S. Pat. No. 4,711,144 to Barr et al., which is herein incorporated byreference for all that it contains, discloses a method of mounting acutter, having a stud portion defining one end thereof and a cuttingformation generally adjacent the other end, in a pocket in a drill bitbody member. The method includes the steps of forming a channelextending into the pocket, inserting brazing material into the channel,inserting the stud portion of the cutter assembly into the pocket, thenheating the bit body member to cause the brazing material to flowthrough the channel into the pocket, and finally re-cooling the bit bodymember. During the assembly of the various pieces required in the stepsmentioned immediately above, a spring is used, cooperative between thecutter and the bit body member, to retain the stud portion in the pocketand also to displace the stud portion toward the trailing side of thepocket.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a drill bit has a bodyintermediate a shank and a working face, the working face comprising aplurality of blades armed on the working face and extending outwardlyfrom the bit body. Each blade comprises at least one cutting element.The drill bit also has a jack element coaxial with an axis of rotationand extending out of an opening formed in the working face. A portion ofthe jack element is coated with a stop-off.

A superhard tip may be bonded to a distal end of the jack element. Thesuperhard tip may comprise a material selected from the group consistingof diamond, polycrystalline diamond, natural diamond, synthetic diamond,vapor deposited diamond, silicon bonded diamond, cobalt bonded diamond,thermally stable diamond, infiltrated diamond, layered diamond,monolithic diamond, polished diamond, course diamond, fine diamond,cubic boron nitride, diamond impregnated matrix, diamond impregnatedcarbide, metal catalyzed diamond, or combinations thereof. The jackelement may have a surface with a concave region. The jack may alsocomprise a material selected from the group consisting of steel, arefractory metal, carbide, tungsten carbide, cemented metal carbide,niobium, titanium, platinum, molybdenum, diamond, cobalt, nickel, iron,cubic boron nitride, and combinations thereof. The jack element mayeither be press fit into a steel sleeve bonded to the working face ofthe drill bit or it may be brazed into or onto the working face of thedrill bit.

The stop-off may have a melting point higher than 1000 degrees Celsius.In some embodiments, the stop-off may be boron nitride. However, inother embodiments, the stop-off may comprise a material selected fromthe group comprising copper, nickel, cobalt, gold, silver, manganese,magnesium, palladium, titanium, niobium, zinc, phosphorous, boron,aluminum, cadmium, chromium, tin, silicon, tantalum, yttrium, metaloxide, ceramic, graphite, alumina or combinations thereof. The stop-offmay be layered onto the jack element.

In another aspect of the invention, a method has steps for manufacturinga drill bit. A drill bit has a working face and an axis of rotation anda bit body intermediate a shank and the working face. A steel sleeve maybe brazed into a pocket formed in the working face of the drill bit. Aportion of the jack element may be covered with a stop-off. The stop-offmay be applied to the jack element by a process of layering, dipping,spraying, brushing, flow coating, rolling, plating, cladding, silkscreen printing, taping, masking or a combination thereof. The jackelement may then be press fit into the steel sleeve and at least onecutting element may be brazed onto the working face adjacent the pressedfit jack element.

The stop-off may be boron nitride or it may comprise a material selectedfrom the group comprising copper, nickel, cobalt, gold, silver,manganese, magnesium, palladium, titanium, niobium, zinc, phosphorous,boron, aluminum, cadmium, chromium, tin, silicon, tantalum, yttrium,metal oxide, ceramic, or combinations thereof. The material may becombined with an acrylic binder that is dissolved in a solvent in orderto form the stop-off. The solvent may comprise xylene, toluene, butylacetate, or a combination thereof.

The stop-off may be non-wetting to a braze used for bonding the cuttingelements onto the working face or the jack element into a pocket formedin the working face. This may be beneficial in that the jack element maybe protected from the braze during the manufacturing process. In someapplications, the portion of the jack element may be covered with astop-off comprising a wax or a lacquer. The jack element may have aconcave region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagram of an embodiment of a drill bitsuspended in a bore hole.

FIG. 2 is a perspective diagram of an embodiment of a drill bit.

FIG. 3 is a cross-sectional diagram of an embodiment of a drill bit.

FIG. 3 a is a cross-sectional diagram of another embodiment of a drillbit.

FIG. 4 is a cross-sectional diagram of another embodiment of a drillbit.

FIG. 5 is a cross-sectional diagram of another embodiment of a drillbit.

FIG. 6 is a cross-sectional diagram of another embodiment of a drillbit.

FIG. 7 is a cross-sectional diagram of another embodiment of a drillbit.

FIG. 8 is a cross-sectional diagram of an embodiment of a jack element.

FIG. 9 is a cross-sectional diagram of another embodiment of a jackelement.

FIG. 10 is a cross-sectional diagram of another embodiment of a jackelement.

FIG. 11 is a cross-sectional diagram of another embodiment of a jackelement.

FIG. 12 is a diagram of an embodiment of a method for manufacturing adrill bit.

FIG. 13 is a diagram of another embodiment of a method for manufacturinga drill bit.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a perspective diagram of an embodiment of a drill string 100suspended by a derrick 101. A bottom hole assembly 102 is located at thebottom of a bore hole 103 and comprises a drill bit 104. As the drillbit 104 rotates downhole the drill string 100 advances farther into theearth. The drill string 100 may penetrate soft or hard subterraneanformations 105. The bottomhole assembly 102 and/or downhole componentsmay comprise data acquisition devices which may gather data. The datamay be sent to the surface via a transmission system to a data swivel106. The data swivel 106 may send the data to the surface equipment.Further, the surface equipment may send data and/or power to downholetools and/or the bottomhole assembly 102. U.S. Pat. No. 6,670,880 whichis herein incorporated by reference for all that it contains, disclosesa telemetry system that may be compatible with the present invention;however, other forms of telemetry may also be compatible such as systemsthat include mud pulse systems, electromagnetic waves, radio waves,and/or short hop. In some embodiments, no telemetry system isincorporated into the drill string.

In the preferred embodiment, a drill bit 104 may have a body 200intermediate a shank 201 and a working face 202 as depicted in FIG. 2. Aplurality blades 250 formed on the working face 202 may extend outwardlyfrom the bit body 200, each blade 250 comprising at least one cuttingelement 203. A jack element 204 may extend out of an opening 205 formedin the working face 202. A portion 206 of the jack element 204 may becoated with a stop-off in order to protect the jack element 204 from abraze 207 used to braze the cutting elements 203 onto the blades 250.During the manufacturing of the drill bit comprising a jack element,high temperatures may cause excess braze 207 from the cutting elements203 proximate the jack element 204 to melt and flow onto the jackelement 204. It is believed that in some embodiments the braze 207 mayweaken the jack element 204 and contribute to damage of the jack elementin a downhole drilling operation. The stop-off may have a meltingtemperature higher than 1000 degrees Celsius. This may be necessarybecause of the high temperatures the drill bit 104 may be exposed toduring the manufacturing process. Preferably, the melting temperature ofthe stop-off may be higher than a melting temperature of the braze 207.The jack element may comprise a material selected from the groupconsisting of a refractory metal, carbide, tungsten carbide, cementedmetal carbide, niobium, titanium, platinum, molybdenum, diamond, cobalt,nickel iron, cubic boron nitride, and combinations thereof. In thepreferred embodiment, the stop-off may comprise boron nitride.

Referring now to FIG. 3, a jack element 204 coaxial with an axis ofrotation 350 may extend out of an opening 205 formed in the working face202 of the drill bit 104. A superhard tip 300 may be bonded to a distalend 301 of the jack element 204 and may comprise a material selectedfrom the group consisting of diamond, polycrystalline diamond, naturaldiamond, synthetic diamond, vapor deposited diamond, silicon bondeddiamond, cobalt bonded diamond, thermally stable diamond, infiltrateddiamond, layered diamond, monolithic diamond, polished diamond, coursediamond, fine diamond, cubic boron nitride, diamond impregnated matrix,diamond impregnated carbide, metal catalyzed diamond, or combinationsthereof. The jack element 204 may be press fit into a steel sleeve 302brazed into a pocket 303 formed in the working face 202 of the drill bit104. The working face 202 may comprise a plurality of blades 250 thatare formed to extend outwardly from the bit body 200, each of which maycomprise at least one cutting element 203. Preferably, the drill bit 104may have between three and seven blades 250. A plurality of nozzles 305may also be fitted into recesses 306 formed in the working face 202.

A portion of the jack element 204 may be covered with a stop-off so asto prevent contact between the jack dement 204 and excess braze that maymelt during the manufacturing of the drill bit 104. In some embodiments,the stop-off may cover a portion 206 of the jack element 204 extendingout of the opening 205 formed in the working face 202. In otherembodiments, the stop-off may cover the whole jack element 204.

FIG. 3 a discloses a drill bit 104 with a jack element 204 brazed withinthe opening directly to the bit body. The stop-off 400 is coated ontothe portion of the jack element below and above the opening 205 of thepocket. The braze 207 is allowed to bond a majority of the surface areaof the jack element to the wall of the pocket, but not the portion ofthe jack element proximate the opening of the pocket. In someembodiments of the invention, the jack element may have a plurality offluid holes. These holes may also be protected from braze material witha stop-off. In some embodiments, the stop-off may actually plug off thefluid holes during manufacturing.

FIGS. 4 through 7 illustrate different embodiments of a jack element 204extending out of the opening 205 formed in the working face 202 of thedrill bit 104. The jack element 204 may be press fit into a steel sleeve302, the steel sleeve 302 being bonded to the working face 202 of thedrill bit 104. The steel sleeve 302 may be brazed within a pocket 303formed into the working face 202. A stop-off 400 may cover a portion 206of the jack element 204. In the preferred embodiment, the stop-off 400may comprise boron nitride. In other embodiments, the stop-off maycomprise a material selected from the group consisting of copper,nickel, cobalt, gold, silver, manganese, magnesium, palladium, titanium,niobium, zinc, phosphorous, boron, aluminum, cadmium, chromium, tin,silicon, tantalum, yttrium, metal oxide, ceramic, graphite, alumina, orcombinations thereof. The stop-off 400 may be formed by combining anaforementioned material with an acrylic binder dissolved in a solvent.The solvent may comprise xylene, toluene, butyl acetate, hydrocarbons,or a combination thereof. The solvents and binders used in forming thestop-off may be dependant on the method of applying the stop-off as wellas the material composition of the jack element. The stop-off may benon-wetting to a material used to braze the cutting elements 203 ontothe working face 202. It is believed that the stop-off may protect thejack element 204 from thermal fluctuations during the manufacturingprocess. Thermal fluctuations may be caused by the molten brazecontacting the jack element, causing the jack element to expand andconstrict with the changing temperatures, thus weakening the jackelement.

In the embodiment of FIG. 4, a stop-off 400 may cover a portion 206 ofthe jack element nearest the cutting elements 203. The portion 206 ofthe jack element 204 extending out of the drill bit may be more prone tocontact with a braze from the cutting elements 203 than other portionsof the jack element 204. However, as shown in the embodiment of FIG. 5,it may be beneficial to cover a larger portion 206 of the jack elementwith the stop-off 400 to ensure that the portion 206 of the jack element204 is protected. In the embodiment of FIG. 6, the stop-off 400 may beapplied to the jack element 204 by taping. In other embodiments, thestop-off may be applied to the jack element by a process of layering,dipping, spraying, brushing, flow coating, rolling, plating, cladding,silk screen printing, masking or a combination thereof. FIG. 7 shows ajack element 204 in which the stop-off 400 is layered. In thisembodiment, the stop-off 400 may be thicker at one segment 700 of thejack element than at another segment 701 of the jack element. The amountof stop-off 400 used to cover a portion 206 of the jack element may varyalong the jack element 204. Layers may be beneficial when the stop-offdoes not bond well to the portion of the jack element. In such a case,the undermost layer of the stop-off may form a good bond with thestop-off and the jack element.

FIGS. 8 through 11 show various embodiments of a jack element 204. Inthe preferred embodiment, the jack element 204 may have a surface 800with a concave region 801, as shown in FIG. 8. In such embodiments, itis believed that forces exerted on the jack element 204 may be moreevenly distributed throughout the jack element. A superhard tip 300 maybe bonded to the distal end 301 of the jack element 204, the tipcomprising a material selected from the group consisting of diamond,polycrystalline diamond, natural diamond, synthetic diamond, vapordeposited diamond, silicon bonded diamond, cobalt bonded diamond,thermally stable diamond, infiltrated diamond, layered diamond,monolithic diamond, polished diamond, course diamond, fine diamond,cubic boron nitride, diamond impregnated matrix, diamond impregnatedcarbide, metal catalyzed diamond, or combinations thereof. The jackelement 204 may comprise a material selected from the group consistingof a refractory metal, carbide, tungsten carbide, cemented metalcarbide, niobium, titanium, platinum, molybdenum, diamond, cobalt,nickel, iron, cubic boron nitride, and combinations thereof. In otherembodiments, the jack element 204 may not have a superhard tip, asillustrated in the embodiment of FIG. 9. In this embodiment, the jackelement 204 may have a surface 800 with a concave region 801. FIG. 10discloses an embodiment of a jack element 204 with a superhard tip 300bonded to the distal end 301 of the jack element 204. The superhard tip300 comprises a flat-sided thick, sharp geometry as well as a curvedinterface 1000 between the superhard tip 300 and the jack element 204.FIG. 11 depicts a jack element 204 with a superhard tip 300 attached tothe distal end 301 of the jack element 204. Nodules 1100 may beincorporated at the interface 1000 between the superhard tip 300 and thejack element 204, which may provide more surface area on the jackelement to provide a stronger interface. This embodiment also shows ajack element 204 comprising a surface 800 with a concave region 801.

FIG. 12 is a diagram of an embodiment of a method 1200 for manufacturinga drill bit. The method 1200 includes providing 1201 a drill bit with aworking face and an axis of rotation and a bit body intermediate a shankand the working face. The method 1200 also includes brazing 1202 a steelsleeve into a pocket formed in the working face of the drill bit. Themethod 1200 further includes covering 1203 a portion of a jack elementwith a stop-off. The stop-off preferably comprises boron nitride.However, it may comprise copper, nickel, cobalt, gold, silver,manganese, magnesium, palladium, titanium, niobium, zinc, phosphorous,boron, aluminum, cadmium, chromium, tin, silicon, tantalum, yttrium,metal oxide, ceramic, or combinations thereof. Covering a portion of thejack element with a stop-off may include applying a wax or lacquer tothe portion. The stop-off may be applied to the jack element by aprocess of layering, dipping, spraying, brushing, flow coating, rolling,plating, cladding, silk screen printing, taping, masking or acombination thereof. The method also includes press fitting 1204 thejack element into the steel sleeve and brazing 1205 at least one cuttingelement onto the working face adjacent the pressed fit jack element. Thestop-off may be non-wetting to a material used in brazing the cuttingelements onto the working face.

In FIG. 13, another method is disclosed. The method may comprise thesteps of providing 1201 a drill bit with a working face and an axis ofrotation and a bit body intermediate a shank and the working face;covering 1203 a portion of a jack element with a stop-off, and brazing1250 the jack element into the working face.

Whereas the present invention has been described in particular relationto the drawings attached hereto, it should be understood that other andfurther modifications apart from those shown or suggested herein, may bemade within the scope and spirit of the present invention.

1. A method for manufacturing a drill bit, comprising the steps of:providing a drill bit with a working face and an axis of rotation and abit body intermediate a shank and the working face; brazing a steelsleeve into a pocket formed in the working face of the drill bit;covering a portion of a jack element with a stop-off; press fitting thejack element into the steel sleeve; and brazing at least one cuttingelement onto the working face adjacent the pressed fit jack element. 2.The method of claim 1, wherein the stop-off comprises boron nitride. 3.The method of claim 1, wherein the stop-off comprises a materialselected from the group comprising copper, nickel, cobalt, gold, silver,manganese, magnesium, palladium, titanium, niobium, zinc, phosphorous,boron, aluminum, cadmium, chromium, tin, silicon, tantalum, yttrium,metal oxide, ceramic, or combinations thereof.
 4. The method of claim 3,wherein the stop-off is formed by combining the material with an acrylicbinder dissolved in a solvent.
 5. The method of claim 4, wherein thesolvent comprises xylene, toluene, butyl acetate, hydrocarbons, or acombination thereof.
 6. The method of claim 1, wherein the stop-off isnon-wetting to a material used to braze the cutting elements onto theworking face.
 7. The method of claim 1, wherein the jack elementcomprises a concave region.
 8. The method of claim 1, wherein the stepof covering a portion of the jack element with a stop-off includesapplying a wax or lacquer to the portion.
 9. The method of claim 1,wherein the stop-off is applied to the jack element by a process oflayering, dipping, spraying, brushing, flow coating, rolling, plating,cladding, silk screen printing, taping, masking or a combinationthereof.
 10. The method of claim 1, wherein a distal end of the jackelement extends beyond the working face.
 11. The method of claim 1,wherein the jack element comprises at least one fluid hole.
 12. Themethod claim 11, wherein the at least one fluid hole is protected with astop-off.
 13. The method of claim 1, wherein the jack element is coaxialwith an axis of rotation of the drill bit.
 14. The method of claim 1,wherein a diamond layer is bonded to a distal end of the jack element.15. The method of claim 1, wherein the stop-off is applied in layers.16. The method of claim 15, wherein the layers comprise differentcompositions.
 17. The method of claim 1, wherein the step of coveringthe jack with stop off includes dipping, spraying, brushing, flowcoating, rolling, plating, cladding, silk screen printing, masking or acombination thereof.
 18. A method for manufacturing a drill bit,comprising the steps of: providing a drill bit with a working face andan axis of rotation and a bit body intermediate a shank and the workingface; covering a portion of a jack element with a stop-off; pressfitting the jack element into the working face; and brazing at least onecutting element onto the working face adjacent the pressed fit jackelement.